use a colormap for implicit_plot3d

edit

I have once managed to get plot3d use a colormap, see here:

import matplotlib.cm
matplotlib.cm.datad.keys()

lists you the colormaps, you can also create your own. Note, the cmsel list in the following snippet defines the actual colors.

var('r v')
cmsel = [matplotlib.cm.get_cmap('autumn')(_) for _ in sxrange(0,1,0.05)]
p = plot3d(0.2*(r**2 + v**2) + cos(2*r)*sin(2*v),(r,-2,2), (v,-2,2), adaptive=True, color=cmsel, plot_points=10, opacity=0.9)
p2 = sphere((0,0,0),1,color='black',opacity=0.5)
(p+p2).show(aspect_ratio=(1,1,1), figsize=[7,3])

I don't know how to comment on another answer, so I'll just post my comment here. You don't have to import matplotlib colormaps, since they are already imported in the sage colormaps object:

sage: var('r v')
sage: cmsel = [colormaps['autumn'](i) for i in sxrange(0,1,0.05)]
sage: p = plot3d(0.2*(r**2 + v**2) + cos(2*r)*sin(2*v),(r,-2,2), (v,-2,2), adaptive=True, color=cmsel, plot_points=10, opacity=0.9)
sage: p2 = sphere((0,0,0),1,color='black',opacity=0.5)
sage: (p+p2).show(aspect_ratio=(1,1,1), figsize=[7,3])

You can see the available colormaps by doing

sage: colormaps.keys()

Thanks for the followup, Niles. This is a really annoying part of some things that are defined in .pyx files - ImplicitSurface is a cdef (Cython) function, and these don't always work well with introspection in my experience. Weirdly, I don't get the traceback you do in the notebook.

It turns out that **kwds (which would include color) end up in the init of IndexFaceSet which sends it to PrimitiveObject in plot3d/base.pyx which includes

    else:
        self.texture = Texture(kwds)

And if you look at THAT you will see that that just goes through a whole slew of possible things the input could be to Texture. And I think that following this the bug is that parse_color does not take a multiplicity of colors.

This still doesn't answer how to GET the colormap, but hopefully tracks down some of why it isn't working.